Hypothesis Testing to Compare 2 Population Means
This lab deals with the problem of comparing the means of two populations using a 2-sample t-test. The application for this lab deals with treating depression using a drug called fluoxetine.
In this lab, we want to see if depressed people improve more on the drug fluoxetine compared to depressed people who were treated with a placebo.
Data for this lab comes from a 12-week study where depressed people in the study were randomized to take either take a depression drug (Treatment =1) or a placebo (Treatment=1) as indicated (Column A).
The outcome is the degree of improvement (column B of the excel data set) in depressive symptoms after 12 weeks (higher scores indicate better outcomes).
1. What is the alternate hypothesis in sentence form and mathematically if H0: µ1-µ2=0?
Conduct a Descriptive Statistics Analysis using Excel Statpak and answer questions 2-5
2. How many of the people in this study were treated with placebo n1 and how many were treated with the drug n2?
n1 = __________
n2 = __________
3. The mean improvement for people treated with the placebo is __________.
The standard deviation for people treated with the placebo is __________.
The mean improvement for people treated with the drug is __________.
The standard deviation for people treated with the drug is __________.
4. Based on the mean improvement for placebo and drug treated subjects, which treatment (placebo or drug) appears to be doing better? Can we be sure one is doing better than the other by just looking at the sample means?
5. The associated test statistic from a comparison of the means test using Excel (re: p. 473 in the text) is __________.
6. The t-test statistic (found by hand) is __________ . Show your work in the space below (note you should get near to the same answer as the test statistic calculated in excel).
7. The associated p-value from this test using Excel (re: p. 473 in the text) is __________.
8. Would you reject or not reject the null based on the p-value_________
9. Confirm your answer by conducting a critical value analysis (no need to upload the diagram)
10. What can we conclude from the t-test? To answer this, write a paragraph interpreting the t-test statistic and the p-value. In your paragraph, answer the following questions:
Does the data support the claim that the drug is more effective than a placebo at the 5% significance level? If the result is not significant at the 5% significance level, can we claim the drug does not work? Can we claim the placebo works better than the drug?
Attachment:- anti depressant.rar